Null data packet frame format

ABSTRACT

This disclosure describes systems, methods, and devices related to null data packet (NDP) frame format. A device may cause to send a null data packet announcement (NDPA) frame to a responding station device (RSTA). The device may cause to send a first sounding NDP frame comprising one or more fields formatted to support 2.4 gigahertz (GHz) and 5 GHz bands in a non-trigger-based ranging measurement with the RSTA. The device may identify after a passage of a short inter-frame space (SIFS) time a second NDP frame received from the RSTA. The device may identify a location measurement report frame from the RSTA.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a Continuation of U.S. Non-Provisional application Ser. No. 16/444,239, filed Jun. 18, 2019, which claims the benefit of U.S. Provisional Application No. 62/686,452, filed Jun. 18, 2018, all disclosures of which are incorporated herein by reference as if set forth in full.

TECHNICAL FIELD

This disclosure generally relates to systems, methods, and devices for wireless communications and, more particularly, null data packet (NDP) frame format.

BACKGROUND

Wireless devices are becoming widely prevalent and are increasingly requesting access to wireless channels. The Institute of Electrical and Electronics Engineers (IEEE) is developing one or more standards that utilize Orthogonal Frequency-Division Multiple Access (OFDMA) in channel allocation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts a diagram illustrating an example network environment of illustrative null data packet (NDP) frame format system, in accordance with one or more example embodiments of the present disclosure.

FIG. 2 depicts an illustrative schematic diagram for NDP frame format, in accordance with one or more example embodiments of the present disclosure.

FIGS. 3A-3D depict illustrative schematic diagrams for NDP frame format, in accordance with one or more example embodiments of the present disclosure.

FIG. 4 depicts a flow diagram of illustrative process for a NDP frame format system, in accordance with one or more embodiments of the disclosure.

FIG. 5 depicts a functional diagram of an example communication station, in accordance with one or more example embodiments of the present disclosure.

FIG. 6 depicts a block diagram of an example machine upon which any of one or more techniques (e.g., methods) may be performed, in accordance with one or more example embodiments of the present disclosure.

FIG. 7 is a block diagram of a radio architecture in accordance with some examples.

FIG. 8 illustrates an example front-end module circuitry for use in the radio architecture of FIG. 7, in accordance with one or more example embodiments of the present disclosure.

FIG. 9 illustrates an example radio IC circuitry for use in the radio architecture of FIG. 7, in accordance with one or more example embodiments of the present disclosure.

FIG. 10 illustrates an example baseband processing circuitry for use in the radio architecture of FIG. 7, in accordance with one or more example embodiments of the present disclosure.

DETAILED DESCRIPTION

The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims.

Currently, in the 802.11az specification, two measurement ranging sequences have been defined: 1) trigger based (e.g., high efficiency ranging (HEz)) sequence and non-trigger based (e.g., very high throughput ranging (VHTz)) sequence. The trigger based sequence is developed based on the 802.11ax specification, and the non-trigger sequence based is developed based on the 802.11ac specification. Different types of null data packet (NDP) frames are defined for the non-secured mode (regular mode) and secured mode of HEz or VHTz. The non-trigger based measurement sequence and the NDP frames are used for the uplink and downlink channel sounding. 802.11az requires the support of both of the 2.4 GHz and 5 GHz bands, but 802.11ac is only defined for 5 GHz frequency band. Therefore, the non-trigger based measurement sequence and the NDP frames used for the uplink and downlink channel sounding are not defined for the 2.4 GHz frequency band. To enable ranging with VHTz on the 2.4 GHz band, new features need to be developed, and several options are proposed in this disclosure.

Example embodiments of the present disclosure relate to systems, methods, and devices for NDP frame format for VHTz at 2.4 GHz.

In one embodiment, an NDP frame format system may facilitate that a VHTz station device (STA) for 2.4 GHz band may enable the VHTz ranging at 2.4 GHz band. This VHTz STA can support VHTz NDP or HEz single user (SU) NDP. The proposed frame format may be backward compatible and may result in minimal implementation complexity. The above descriptions are for purposes of illustration and are not meant to be limiting. Numerous other examples, configurations, processes, etc., may exist, some of which are described in detail below. Example embodiments will now be described with reference to the accompanying figures.

FIG. 1 is a diagram illustrating an example network environment, in accordance with one or more example embodiments of the present disclosure. Wireless network 100 may include one or more user devices 120 and one or more access point(s) (AP) 102, which may communicate in accordance with IEEE 802.11 communication standards. The user device(s) 120 may be mobile devices that are non-stationary (e.g., not having fixed locations) or may be stationary devices.

In some embodiments, the user devices 120, and the AP(s) 102 may include one or more computer systems similar to that of the functional diagram of FIG. 5 and/or the example machine/system of FIG. 6.

One or more illustrative user device(s) 120 and/or AP(s) 102 may be operable by one or more user(s) 110. It should be noted that any addressable unit may be a station (STA). An STA may take on multiple distinct characteristics, each of which shape its function. For example, a single addressable unit might simultaneously be a portable STA, a quality-of-service (QoS) STA, a dependent STA, and a hidden STA. The one or more illustrative user device(s) 120 and the AP(s) 102 may be STAs. The one or more illustrative user device(s) 120 and/or AP(s) 102 may operate as a personal basic service set (PBSS) control point/access point (PCP/AP). The user device(s) 120 (e.g., 124, 126, or 128) and/or AP(s) 102 may include any suitable processor-driven device including, but not limited to, a mobile device or a non-mobile, e.g., a static, device. For example, user device(s) 120 and/or AP(s) 102 may include, a user equipment (UE), a station (STA), an access point (AP), a software enabled AP (SoftAP), a personal computer (PC), a wearable wireless device (e.g., bracelet, watch, glasses, ring, etc.), a desktop computer, a mobile computer, a laptop computer, an Ultrabook™ computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a handheld device, an internet of things (IoT) device, a sensor device, a PDA device, a handheld PDA device, an on-board device, an off-board device, a hybrid device (e.g., combining cellular phone functionalities with PDA device functionalities), a consumer device, a vehicular device, a non-vehicular device, a mobile or portable device, a non-mobile or non-portable device, a mobile phone, a cellular telephone, a PCS device, a PDA device which incorporates a wireless communication device, a mobile or portable GPS device, a DVB device, a relatively small computing device, a non-desktop computer, a “carry small live large” (CSLL) device, an ultra mobile device (UMD), an ultra mobile PC (UMPC), a mobile internet device (MID), an “origami” device or computing device, a device that supports dynamically composable computing (DCC), a context-aware device, a video device, an audio device, an A/V device, a set-top-box (STB), a blu-ray disc (BD) player, a BD recorder, a digital video disc (DVD) player, a high definition (HD) DVD player, a DVD recorder, a HD DVD recorder, a personal video recorder (PVR), a broadcast HD receiver, a video source, an audio source, a video sink, an audio sink, a stereo tuner, a broadcast radio receiver, a flat panel display, a personal media player (PMP), a digital video camera (DVC), a digital audio player, a speaker, an audio receiver, an audio amplifier, a gaming device, a data source, a data sink, a digital still camera (DSC), a media player, a smartphone, a television, a music player, or the like. Other devices, including smart devices such as lamps, climate control, car components, household components, appliances, etc. may also be included in this list.

As used herein, the term “Internet of Things (IoT) device” is used to refer to any object (e.g., an appliance, a sensor, etc.) that has an addressable interface (e.g., an Internet protocol (IP) address, a Bluetooth identifier (ID), a near-field communication (NFC) ID, etc.) and can transmit information to one or more other devices over a wired or wireless connection. An IoT device may have a passive communication interface, such as a quick response (QR) code, a radio-frequency identification (RFID) tag, an NFC tag, or the like, or an active communication interface, such as a modem, a transceiver, a transmitter-receiver, or the like. An IoT device can have a particular set of attributes (e.g., a device state or status, such as whether the IoT device is on or off, open or closed, idle or active, available for task execution or busy, and so on, a cooling or heating function, an environmental monitoring or recording function, a light-emitting function, a sound-emitting function, etc.) that can be embedded in and/or controlled/monitored by a central processing unit (CPU), microprocessor, ASIC, or the like, and configured for connection to an IoT network such as a local ad-hoc network or the Internet. For example, IoT devices may include, but are not limited to, refrigerators, toasters, ovens, microwaves, freezers, dishwashers, dishes, hand tools, clothes washers, clothes dryers, furnaces, air conditioners, thermostats, televisions, light fixtures, vacuum cleaners, sprinklers, electricity meters, gas meters, etc., so long as the devices are equipped with an addressable communications interface for communicating with the IoT network. IoT devices may also include cell phones, desktop computers, laptop computers, tablet computers, personal digital assistants (PDAs), etc. Accordingly, the IoT network may be comprised of a combination of “legacy” Internet-accessible devices (e.g., laptop or desktop computers, cell phones, etc.) in addition to devices that do not typically have Internet-connectivity (e.g., dishwashers, etc.).

The user device(s) 120 and/or AP(s) 102 may also include mesh stations in, for example, a mesh network, in accordance with one or more IEEE 802.11 standards and/or 3GPP standards.

Any of the user device(s) 120 (e.g., user devices 124, 126, 128), and AP(s) 102 may be configured to communicate with each other via one or more communications networks 130 and/or 135 wirelessly or wired. The user device(s) 120 may also communicate peer-to-peer or directly with each other with or without the AP(s) 102. Any of the communications networks 130 and/or 135 may include, but not limited to, any one of a combination of different types of suitable communications networks such as, for example, broadcasting networks, cable networks, public networks (e.g., the Internet), private networks, wireless networks, cellular networks, or any other suitable private and/or public networks. Further, any of the communications networks 130 and/or 135 may have any suitable communication range associated therewith and may include, for example, global networks (e.g., the Internet), metropolitan area networks (MANs), wide area networks (WANs), local area networks (LANs), or personal area networks (PANs). In addition, any of the communications networks 130 and/or 135 may include any type of medium over which network traffic may be carried including, but not limited to, coaxial cable, twisted-pair wire, optical fiber, a hybrid fiber coaxial (HFC) medium, microwave terrestrial transceivers, radio frequency communication mediums, white space communication mediums, ultra-high frequency communication mediums, satellite communication mediums, or any combination thereof.

Any of the user device(s) 120 (e.g., user devices 124, 126, 128) and AP(s) 102 may include one or more communications antennas. The one or more communications antennas may be any suitable type of antennas corresponding to the communications protocols used by the user device(s) 120 (e.g., user devices 124, 126 and 128), and AP(s) 102. Some non-limiting examples of suitable communications antennas include Wi-Fi antennas, Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards compatible antennas, directional antennas, non-directional antennas, dipole antennas, folded dipole antennas, patch antennas, multiple-input multiple-output (MIMO) antennas, omnidirectional antennas, quasi-omnidirectional antennas, or the like. The one or more communications antennas may be communicatively coupled to a radio component to transmit and/or receive signals, such as communications signals to and/or from the user devices 120 and/or AP(s) 102.

Any of the user device(s) 120 (e.g., user devices 124, 126, 128), and AP(s) 102 may be configured to perform directional transmission and/or directional reception in conjunction with wirelessly communicating in a wireless network. Any of the user device(s) 120 (e.g., user devices 124, 126, 128), and AP(s) 102 may be configured to perform such directional transmission and/or reception using a set of multiple antenna arrays (e.g., DMG antenna arrays or the like). Each of the multiple antenna arrays may be used for transmission and/or reception in a particular respective direction or range of directions. Any of the user device(s) 120 (e.g., user devices 124, 126, 128), and AP(s) 102 may be configured to perform any given directional transmission towards one or more defined transmit sectors. Any of the user device(s) 120 (e.g., user devices 124, 126, 128), and AP(s) 102 may be configured to perform any given directional reception from one or more defined receive sectors.

MIMO beamforming in a wireless network may be accomplished using RF beamforming and/or digital beamforming. In some embodiments, in performing a given MIMO transmission, user devices 120 and/or AP(s) 102 may be configured to use all or a subset of its one or more communications antennas to perform MIMO beamforming.

Any of the user devices 120 (e.g., user devices 124, 126, 128), and AP(s) 102 may include any suitable radio and/or transceiver for transmitting and/or receiving radio frequency (RF) signals in the bandwidth and/or channels corresponding to the communications protocols utilized by any of the user device(s) 120 and AP(s) 102 to communicate with each other. The radio components may include hardware and/or software to modulate and/or demodulate communications signals according to pre-established transmission protocols. The radio components may further have hardware and/or software instructions to communicate via one or more Wi-Fi and/or Wi-Fi direct protocols, as standardized by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards.

Some embodiments may be used in conjunction with devices and/or networks operating in accordance with existing. Wireless Fidelity (Wi-Fi) Alliance (WFA) Specifications, including Wi-Fi Neighbor Awareness Networking (NAN) Technical Specification (e.g., NAN and NAN2) and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing WFA Peer-to-Peer (P2P) specifications and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing Wireless-Gigabit-Alliance (WGA) specifications (Wireless Gigabit Alliance, Inc. WiGig MAC and PHY Specification) and/or future versions and/or derivatives thereof, devices and/or networks operating in accordance with existing IEEE 802.11 standards and/or amendments (e.g., 802.11b, 802.11g, 802.11n, 802.11ac, 802.11ax, 802.11ad, 802.11ay, 802.11az, etc.).

In certain example embodiments, the radio component, in cooperation with the communications antennas, may be configured to communicate via 2.4 GHz channels (e.g. 802.11b, 802.11g, 802.11n, 802.11ax), 5 GHz channels (e.g. 802.11n, 802.11ac, 802.11ax), or 60 GHZ channels (e.g. 802.11ad). In some embodiments, non-Wi-Fi protocols may be used for communications between devices, such as Bluetooth, dedicated short-range communication (DSRC), Ultra-High Frequency (UHF) (e.g. IEEE 802.11af, IEEE 802.22), white band frequency (e.g., white spaces), or other packetized radio communications. The radio component may include any known receiver and baseband suitable for communicating via the communications protocols. The radio component may further include a low noise amplifier (LNA), additional signal amplifiers, an analog-to-digital (A/D) converter, one or more buffers, and digital baseband.

In one embodiment, and with reference to FIG. 1, a user device 120 may be in communication with one or more APs 102.

For example, AP 102 may communicate with a user device 120 by sending an NDP frame 140. It is understood that the above descriptions are for purposes of illustration and are not meant to be limiting.

FIG. 2 depicts an illustrative schematic diagram for NDP frame format, in accordance with one or more example embodiments of the present disclosure.

Referring to FIG. 2, there is shown a frame exchange to implement a mechanism for the determination of relative range with secure and unsecure measurement and measurement results exchange between an initiator device (initiating STA (ISTA)) and a responder device (responding STA (RSTA)). That is, a mechanism to implement a ranging measurement sequence of frame exchanges defined for a 5 GHz band between the ISTA and the RSTA. The initiator device is shown to be in communication with the responder device that may exchange one or more frames (e.g., NDPA 201, NDP 203, NDP 205, and location measurement report 207 frames) in order to perform ranging measurement in a 5 GHz band to determine a range associated with the initiator device. The initiator device may send the NDPA 201 to the responder device in order to initiate a ranging measurement to determine a range associated with the initiator device. The initiator device may then send, after the passage of a short inter-frame space (SIFS) time 202, the NDP 203 to the responder device. After responder device receives the NDP 203, the responder device may wait for a SIFS time before sending the NDP 205 to the initiator device. After the passage of a SIFS time, the responder device may send information associated with the ranging measurements using the location measurement report 207 frame that is sent from the responder device to the initiator device. The location measurement report frame 207 comprises information that may assist the initiator device to determine its range to responder device.

In 802.11az, two measurement ranging sequences have been defined: 1) trigger based (e.g., high efficiency ranging (HEz)) sequence and non-trigger based (e.g., very high throughput ranging (VHTz)) sequence. The trigger based sequence is developed based on the 802.11ax specification, and the non-trigger sequence based is developed based on the 802.11ac specification. Different types of null data packet (NDP) frames are defined for the non-secured mode and secured mode of HEz or VHTz. The non-trigger based measurement sequence and the NDP frames are used for the uplink and downlink channel sounding. 802.11az is designed to support both of the 2.4 GHz and 5 GHz bands, but 802.11ac is only defined for 5 GHz band. To enable ranging with VHTz on the 2.4 GHz band, new features need to be developed, and several options are proposed in this disclosure.

The VHTz measurement sequence is shown in FIG. 2, and the NDP frames are used for the uplink and downlink channel sounding. 802.11az is designed to support both of the 2.4 GHz and 5 GHz bands, but 802.11ac is only defined for 5 GHz band. To enable ranging with VHTz on the 2.4 GHz band, new features need to be developed.

FIGS. 3A-3D depict illustrative schematic diagrams for NDP frame format, in accordance with one or more example embodiments of the present disclosure.

Referring to FIG. 3A, there is shown a non-trigger based measurement sequence that may be implemented for a 2.4 GHz frequency band.

In one or more embodiments, an NDP frame format system may define a VHTz STA for 2.4 GHz band. The initiator device is shown to be in communication with the responder device that may exchange one or more frames (e.g., NDPA 301, VHT sounding NDP 303, VHT sounding NDP 305, and a location measurement report 307 frames) in order to perform ranging measurement in a 2.4 GHz band to determine a range associated with the initiator device. The initiator device may send the NDPA 301 to the responder device in order to initiate a ranging measurement to determine a range associated with the initiator device. The initiator device may then send, after the passage of a short inter-frame space (SIFS) time, the VHT sounding NDP 303 to the responder device. After responder device receives the VHT sounding NDP 303, the responder device may wait for a SIFS time before sending a VHT sounding NDP 305 to the initiator device. After the passage of a SIFS time, the responder device may send information associated with the ranging measurements using the location measurement report 307 that is sent from the responder device to the initiator device. The location measurement report 307 comprises information that may assist the initiator device to determine its range.

In one or more embodiments, the VHTz STA at 2.4 GHz may also support a VHTz NDP frame defined for 5 GHz. For the secured or non-secured VHTz NDP frames at 5 GHz band, and the VHTz STA at 2.4 GHz may support these NDP frame formats to enable the VHTz ranging at 2.4 GHz.

In one or more embodiments, the VHTz STA at 2.4 GHz may also support the high efficiency (HE) SU sounding NDP PPDU. For the secured or non-secured VHTz NDP frames at 5 GHz band, the VHTz STA at 2.4 GHz may support the HE SU sounding NDP frame format. For the non-secured mode, the HE SU NDP is the same as the 802.11ax SU sounding NDP PPDU, and for the secured mode, the 802.11az may determine the NDP format as shown in FIG. 3B or FIG. 3C.

Referring to FIG. 3B, there is shown an NDP frame 330 that comprises one or more fields. For example, the NDP frame 330 comprises a legacy short training field (L-STF) field, legacy long training field (L-LTF), a legacy signaling field (L-SIG), a repeat L-SIG (RL-SIG) field, an high efficiency signaling A (HE-SIG-A) field, an HE-STF field, and an HEz-LTF field 312. In one or more embodiments, the number of HE-LTF symbols in an HE Ranging NDP depends on the number of space-time streams (Nsts). For example, the HEz-LTF field 312 may be comprised of one or more symbols (e.g., symbol1, . . . Symbol Nsts). In one or more embodiments, the symbols may be preceded by a zero power guard interval (GI) (e.g., zero power GI 314 and 316, etc.) in HEz-LTF field 312. The NDP frame 330 also has a packet extension (PE) field that is 4 μs in duration. When using secure HE-LTFs, the PE will start with a zero-power GI 318.

For the HEz SU sounding NDP with multiple HEz LTF fields, the following format is defined below, and the VHTz STA at 2.4 GHz would also support the NDP format shown in FIG. 3C.

Referring to FIG. 3C, there is shown an NDP frame 350 and a VHTz measurement sequence to support 2.4 GHz frequency band. In this figure, the NDP frame 350 may comprise a L-STF field, a L-LTF field, a L-SIG field, a RL-SIG field, a HE-SIG-A field, a HE-STF field, and a plurality of HE-LTF fields 322. The HE-LTF fields 322 may be comprised of multiple HE-LTF fields, for example, a first HE-LTF field 324, and a last HE-LTF field 326. Also should be understood that each HE-LTF field (e.g., 324 and 326) are comprised of one or more symbols as in FIG. 3B. Also, each symbol may be preceded by a zero power guard interval. The NDP frame 350 also has a packet extension (PE) field that is 4 μs in duration. When using secure HE-LTFs, the PE will comprise a zero-power GI 328 which is located at the beginning of the PE.

Referring to FIG. 3D, there is shown a VHTz measurement sequence to support 2.4 GHz frequency band. For example, in FIG. 3D, there is shown an initiator device that is in communication with a responder device. The initiator device and the responder device may exchange one or more frames (e.g., NDPA 331, HE ranging NDP 333, HE ranging NDP 335, and a location measurement report 337 frames) in order to perform ranging measurement in a 2.4 GHz band to determine a range associated with the initiator device. The initiator device may send the NDPA 331 to the responder device in order to initiate a ranging measurement to determine a range associated with the initiator device. The initiator device may then send, after the passage of a short inter-frame space (SIFS) time, the HE ranging NDP 333 to the responder device. After responder device receives the HE ranging NDP 333, the responder device may wait for a SIFS time before sending the HE ranging NDP 335 to the initiator device. After the passage of a SIFS time, the responder device may send information associated with the ranging measurements using a location measurement report 337 that is sent from the responder device to the initiator device. The location measurement report 337 comprises information that may assist the initiator device to determine its range.

In addition to the NDP frame formats, the VHTz STA may also support the other frame exchanges for VHTz at 5 GHz, for example, the NDPA format and location measurement report format and frame format for negotiation phase and discover phase. For implementation simplicity, the VHTz at 5 GHz can also use the sequence defined in FIG. 3D, so that the HEz SU sounding NPD PPDU can be reused for VHTz, and there is no need to define a new NDP frame for VHTz. It is understood that the above descriptions are for purposes of illustration and are not meant to be limiting.

FIG. 4 illustrates a flow diagram of illustrative process 400 for an illustrative NDP frame format system, in accordance with one or more example embodiments of the present disclosure.

At block 402, a device (e.g., the user device(s) 120 (initiating STA (ISTA)) and/or the AP 102 (responding STA (RSTA)) of FIG. 1) may cause to send a null data packet announcement (NDPA) frame to a responding station device (RSTA).

At block 404, the device may cause to send a first sounding null data packet (NDP) frame comprising one or more fields formatted to support 2.4 gigahertz (GHz) and 5 GHz bands in a non-trigger-based ranging measurement with the RSTA.

At block 406, the device may identify after a passage of a short inter-frame space (SIFS) time a second NDP frame received from the RSTA.

At block 408, the device may identify a location measurement report frame from the RSTA.

It is understood that the above descriptions are for purposes of illustration and are not meant to be limiting.

FIG. 5 shows a functional diagram of an exemplary communication station 500 in accordance with some embodiments. In one embodiment, FIG. 5 illustrates a functional block diagram of a communication station that may be suitable for use as an AP 102 (FIG. 1) or user device 120 (FIG. 1) in accordance with some embodiments. The communication station 500 may also be suitable for use as a handheld device, a mobile device, a cellular telephone, a smartphone, a tablet, a netbook, a wireless terminal, a laptop computer, a wearable computer device, a femtocell, a high data rate (HDR) subscriber station, an access point, an access terminal, or other personal communication system (PCS) device.

The communication station 500 may include communications circuitry 502 and a transceiver 510 for transmitting and receiving signals to and from other communication stations using one or more antennas 501. The transceiver 510 may be a device comprising both a transmitter and a receiver that are combined and share common circuitry (e.g., communication circuitry 502). The communication circuitry 502 may include amplifiers, filters, mixers, analog to digital and/or digital to analog converters. The transceiver 510 may transmit and receive analog or digital signals. The transceiver 510 may allow reception of signals during transmission periods. This mode is known as full-duplex, and may require the transmitter and receiver to operate on different frequencies to minimize interference between the transmitted signal and the received signal. The transceiver 510 may operate in a half-duplex mode, where the transceiver 510 may transmit or receive signals in one direction at a time.

The communications circuitry 502 may include circuitry that can operate the physical layer (PHY) communications and/or medium access control (MAC) communications for controlling access to the wireless medium, and/or any other communications layers for transmitting and receiving signals. The communication station 500 may also include processing circuitry 506 and memory 508 arranged to perform the operations described herein. In some embodiments, the communications circuitry 502 and the processing circuitry 506 may be configured to perform operations detailed in detailed in FIGS. 1-4.

In accordance with some embodiments, the communications circuitry 502 may be arranged to contend for a wireless medium and configure frames or packets for communicating over the wireless medium. The communications circuitry 502 may be arranged to transmit and receive signals. The communications circuitry 502 may also include circuitry for modulation/demodulation, upconversion/downconversion, filtering, amplification, etc. In some embodiments, the processing circuitry 506 of the communication station 500 may include one or more processors. In other embodiments, two or more antennas 501 may be coupled to the communications circuitry 502 arranged for sending and receiving signals. The memory 508 may store information for configuring the processing circuitry 506 to perform operations for configuring and transmitting message frames and performing the various operations described herein. The memory 508 may include any type of memory, including non-transitory memory, for storing information in a form readable by a machine (e.g., a computer). For example, the memory 508 may include a computer-readable storage device, read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices and other storage devices and media.

In some embodiments, the communication station 500 may be part of a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), a wearable computer device, or another device that may receive and/or transmit information wirelessly.

In some embodiments, the communication station 500 may include one or more antennas 501. The antennas 501 may include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas, or other types of antennas suitable for transmission of RF signals. In some embodiments, instead of two or more antennas, a single antenna with multiple apertures may be used. In these embodiments, each aperture may be considered a separate antenna. In some multiple-input multiple-output (MIMO) embodiments, the antennas may be effectively separated for spatial diversity and the different channel characteristics that may result between each of the antennas and the antennas of a transmitting station.

In some embodiments, the communication station 500 may include one or more of a keyboard, a display, a non-volatile memory port, multiple antennas, a graphics processor, an application processor, speakers, and other mobile device elements. The display may be an LCD screen including a touch screen.

Although the communication station 500 is illustrated as having several separate functional elements, two or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may include one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements of the communication station 500 may refer to one or more processes operating on one or more processing elements.

Certain embodiments may be implemented in one or a combination of hardware, firmware, and software. Other embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transitory memory mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a computer-readable storage device may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, and other storage devices and media. In some embodiments, the communication station 500 may include one or more processors and may be configured with instructions stored on a computer-readable storage device memory.

FIG. 6 illustrates a block diagram of an example of a machine 600 or system upon which any one or more of the techniques (e.g., methodologies) discussed herein may be performed. In other embodiments, the machine 600 may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine 600 may operate in the capacity of a server machine, a client machine, or both in server-client network environments. In an example, the machine 600 may act as a peer machine in peer-to-peer (P2P) (or other distributed) network environments. The machine 600 may be a personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile telephone, a wearable computer device, a web appliance, a network router, a switch or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine, such as a base station. Further, while only a single machine is illustrated, the term “machine” shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), or other computer cluster configurations.

Examples, as described herein, may include or may operate on logic or a number of components, modules, or mechanisms. Modules are tangible entities (e.g., hardware) capable of performing specified operations when operating. A module includes hardware. In an example, the hardware may be specifically configured to carry out a specific operation (e.g., hardwired). In another example, the hardware may include configurable execution units (e.g., transistors, circuits, etc.) and a computer readable medium containing instructions where the instructions configure the execution units to carry out a specific operation when in operation. The configuring may occur under the direction of the executions units or a loading mechanism. Accordingly, the execution units are communicatively coupled to the computer-readable medium when the device is operating. In this example, the execution units may be a member of more than one module. For example, under operation, the execution units may be configured by a first set of instructions to implement a first module at one point in time and reconfigured by a second set of instructions to implement a second module at a second point in time.

The machine (e.g., computer system) 600 may include a hardware processor 602 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 604 and a static memory 606, some or all of which may communicate with each other via an interlink (e.g., bus) 608. The machine 600 may further include a power management device 632, a graphics display device 610, an alphanumeric input device 612 (e.g., a keyboard), and a user interface (UI) navigation device 614 (e.g., a mouse). In an example, the graphics display device 610, alphanumeric input device 612, and UI navigation device 614 may be a touch screen display. The machine 600 may additionally include a storage device (i.e., drive unit) 616, a signal generation device 618 (e.g., a speaker), a NDP frame format device 619, a network interface device/transceiver 620 coupled to antenna(s) 630, and one or more sensors 628, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or other sensor. The machine 600 may include an output controller 634, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.)).

The storage device 616 may include a machine readable medium 622 on which is stored one or more sets of data structures or instructions 624 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 624 may also reside, completely or at least partially, within the main memory 604, within the static memory 606, or within the hardware processor 602 during execution thereof by the machine 600. In an example, one or any combination of the hardware processor 602, the main memory 604, the static memory 606, or the storage device 616 may constitute machine-readable media.

The NDP frame format device 619 may carry out or perform any of the operations and processes (e.g., process 400) described and shown above.

It is understood that the above are only a subset of what the NDP frame format device 619 may be configured to perform and that other functions included throughout this disclosure may also be performed by the NDP frame format device 619.

While the machine-readable medium 622 is illustrated as a single medium, the term “machine-readable medium” may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 624.

Various embodiments may be implemented fully or partially in software and/or firmware. This software and/or firmware may take the form of instructions contained in or on a non-transitory computer-readable storage medium. Those instructions may then be read and executed by one or more processors to enable performance of the operations described herein. The instructions may be in any suitable form, such as but not limited to source code, compiled code, interpreted code, executable code, static code, dynamic code, and the like. Such a computer-readable medium may include any tangible non-transitory medium for storing information in a form readable by one or more computers, such as but not limited to read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; a flash memory, etc.

The term “machine-readable medium” may include any medium that is capable of storing, encoding, or carrying instructions for execution by the machine 600 and that cause the machine 600 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding, or carrying data structures used by or associated with such instructions. Non-limiting machine-readable medium examples may include solid-state memories and optical and magnetic media. In an example, a massed machine-readable medium includes a machine-readable medium with a plurality of particles having resting mass. Specific examples of massed machine-readable media may include non-volatile memory, such as semiconductor memory devices (e.g., electrically programmable read-only memory (EPROM), or electrically erasable programmable read-only memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; and CD-ROM and DVD-ROM disks.

The instructions 624 may further be transmitted or received over a communications network 626 using a transmission medium via the network interface device/transceiver 620 utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communications networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), plain old telephone (POTS) networks, wireless data networks (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards known as Wi-Fi®, IEEE 802.16 family of standards known as WiMax®), IEEE 802.15.4 family of standards, and peer-to-peer (P2P) networks, among others. In an example, the network interface device/transceiver 620 may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network 626. In an example, the network interface device/transceiver 620 may include a plurality of antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. The term “transmission medium” shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the machine 600 and includes digital or analog communications signals or other intangible media to facilitate communication of such software. The operations and processes described and shown above may be carried out or performed in any suitable order as desired in various implementations. Additionally, in certain implementations, at least a portion of the operations may be carried out in parallel. Furthermore, in certain implementations, less than or more than the operations described may be performed.

FIG. 7 is a block diagram of a radio architecture 105A, 105B in accordance with some embodiments that may be implemented in any one of the example AP 102 and/or the example user device 120 of FIG. 1. Radio architecture 105A, 105B may include radio front-end module (FEM) circuitry 704 a-b, radio IC circuitry 706 a-b and baseband processing circuitry 708 a-b. Radio architecture 105A, 105B as shown includes both Wireless Local Area Network (WLAN) functionality and Bluetooth (BT) functionality although embodiments are not so limited. In this disclosure, “WLAN” and “Wi-Fi” are used interchangeably.

FEM circuitry 704 a-b may include a WLAN or Wi-Fi FEM circuitry 704 a and a Bluetooth (BT) FEM circuitry 704 b. The WLAN FEM circuitry 704 a may include a receive signal path comprising circuitry configured to operate on WLAN RF signals received from one or more antennas 701, to amplify the received signals and to provide the amplified versions of the received signals to the WLAN radio IC circuitry 706 a for further processing. The BT FEM circuitry 704 b may include a receive signal path which may include circuitry configured to operate on BT RF signals received from one or more antennas 701, to amplify the received signals and to provide the amplified versions of the received signals to the BT radio IC circuitry 706 b for further processing. FEM circuitry 704 a may also include a transmit signal path which may include circuitry configured to amplify WLAN signals provided by the radio IC circuitry 706 a for wireless transmission by one or more of the antennas 701. In addition, FEM circuitry 704 b may also include a transmit signal path which may include circuitry configured to amplify BT signals provided by the radio IC circuitry 706 b for wireless transmission by the one or more antennas. In the embodiment of FIG. 7, although FEM 704 a and FEM 704 b are shown as being distinct from one another, embodiments are not so limited, and include within their scope the use of an FEM (not shown) that includes a transmit path and/or a receive path for both WLAN and BT signals, or the use of one or more FEM circuitries where at least some of the FEM circuitries share transmit and/or receive signal paths for both WLAN and BT signals.

Radio IC circuitry 706 a-b as shown may include WLAN radio IC circuitry 706 a and BT radio IC circuitry 706 b. The WLAN radio IC circuitry 706 a may include a receive signal path which may include circuitry to down-convert WLAN RF signals received from the FEM circuitry 704 a and provide baseband signals to WLAN baseband processing circuitry 708 a. BT radio IC circuitry 706 b may in turn include a receive signal path which may include circuitry to down-convert BT RF signals received from the FEM circuitry 704 b and provide baseband signals to BT baseband processing circuitry 708 b. WLAN radio IC circuitry 706 a may also include a transmit signal path which may include circuitry to up-convert WLAN baseband signals provided by the WLAN baseband processing circuitry 708 a and provide WLAN RF output signals to the FEM circuitry 704 a for subsequent wireless transmission by the one or more antennas 701. BT radio IC circuitry 706 b may also include a transmit signal path which may include circuitry to up-convert BT baseband signals provided by the BT baseband processing circuitry 708 b and provide BT RF output signals to the FEM circuitry 704 b for subsequent wireless transmission by the one or more antennas 701. In the embodiment of FIG. 7, although radio IC circuitries 706 a and 706 b are shown as being distinct from one another, embodiments are not so limited, and include within their scope the use of a radio IC circuitry (not shown) that includes a transmit signal path and/or a receive signal path for both WLAN and BT signals, or the use of one or more radio IC circuitries where at least some of the radio IC circuitries share transmit and/or receive signal paths for both WLAN and BT signals.

Baseband processing circuitry 708 a-b may include a WLAN baseband processing circuitry 708 a and a BT baseband processing circuitry 708 b. The WLAN baseband processing circuitry 708 a may include a memory, such as, for example, a set of RAM arrays in a Fast Fourier Transform or Inverse Fast Fourier Transform block (not shown) of the WLAN baseband processing circuitry 708 a. Each of the WLAN baseband circuitry 708 a and the BT baseband circuitry 708 b may further include one or more processors and control logic to process the signals received from the corresponding WLAN or BT receive signal path of the radio IC circuitry 706 a-b, and to also generate corresponding WLAN or BT baseband signals for the transmit signal path of the radio IC circuitry 706 a-b. Each of the baseband processing circuitries 708 a and 708 b may further include physical layer (PHY) and medium access control layer (MAC) circuitry, and may further interface with a device for generation and processing of the baseband signals and for controlling operations of the radio IC circuitry 706 a-b.

Referring still to FIG. 7, according to the shown embodiment, WLAN-BT coexistence circuitry 713 may include logic providing an interface between the WLAN baseband circuitry 708 a and the BT baseband circuitry 708 b to enable use cases requiring WLAN and BT coexistence. In addition, a switch 703 may be provided between the WLAN FEM circuitry 704 a and the BT FEM circuitry 704 b to allow switching between the WLAN and BT radios according to application needs. In addition, although the antennas 701 are depicted as being respectively connected to the WLAN FEM circuitry 704 a and the BT FEM circuitry 704 b, embodiments include within their scope the sharing of one or more antennas as between the WLAN and BT FEMs, or the provision of more than one antenna connected to each of FEM 704 a or 704 b.

In some embodiments, the front-end module circuitry 704 a-b, the radio IC circuitry 706 a-b, and baseband processing circuitry 708 a-b may be provided on a single radio card, such as wireless radio card 702. In some other embodiments, the one or more antennas 701, the FEM circuitry 704 a-b and the radio IC circuitry 706 a-b may be provided on a single radio card. In some other embodiments, the radio IC circuitry 706 a-b and the baseband processing circuitry 708 a-b may be provided on a single chip or integrated circuit (IC), such as IC 712.

In some embodiments, the wireless radio card 702 may include a WLAN radio card and may be configured for Wi-Fi communications, although the scope of the embodiments is not limited in this respect. In some of these embodiments, the radio architecture 105A, 105B may be configured to receive and transmit orthogonal frequency division multiplexed (OFDM) or orthogonal frequency division multiple access (OFDMA) communication signals over a multicarrier communication channel. The OFDM or OFDMA signals may comprise a plurality of orthogonal subcarriers.

In some of these multicarrier embodiments, radio architecture 105A, 105B may be part of a Wi-Fi communication station (STA) such as a wireless access point (AP), a base station or a mobile device including a Wi-Fi device. In some of these embodiments, radio architecture 105A, 105B may be configured to transmit and receive signals in accordance with specific communication standards and/or protocols, such as any of the Institute of Electrical and Electronics Engineers (IEEE) standards including, 802.11n-2009, IEEE 802.11-2012, IEEE 802.11-2016, 802.11n-2009, 802.11ac, 802.11ah, 802.11ad, 802.11 ay and/or 802.11ax standards and/or proposed specifications for WLANs, although the scope of embodiments is not limited in this respect. Radio architecture 105A, 105B may also be suitable to transmit and/or receive communications in accordance with other techniques and standards.

In some embodiments, the radio architecture 105A, 105B may be configured for high-efficiency Wi-Fi (HEW) communications in accordance with the IEEE 802.11ax standard. In these embodiments, the radio architecture 105A, 105B may be configured to communicate in accordance with an OFDMA technique, although the scope of the embodiments is not limited in this respect.

In some other embodiments, the radio architecture 105A, 105B may be configured to transmit and receive signals transmitted using one or more other modulation techniques such as spread spectrum modulation (e.g., direct sequence code division multiple access (DS-CDMA) and/or frequency hopping code division multiple access (FH-CDMA)), time-division multiplexing (TDM) modulation, and/or frequency-division multiplexing (FDM) modulation, although the scope of the embodiments is not limited in this respect.

In some embodiments, as further shown in FIG. 6, the BT baseband circuitry 708 b may be compliant with a Bluetooth (BT) connectivity standard such as Bluetooth, Bluetooth 8.0 or Bluetooth 6.0, or any other iteration of the Bluetooth Standard.

In some embodiments, the radio architecture 105A, 105B may include other radio cards, such as a cellular radio card configured for cellular (e.g., SGPP such as LTE, LTE-Advanced or 7G communications).

In some IEEE 802.11 embodiments, the radio architecture 105A, 105B may be configured for communication over various channel bandwidths including bandwidths having center frequencies of about 900 MHz, 2.4 GHz, 5 GHz, and bandwidths of about 2 MHz, 4 MHz, 5 MHz, 5.5 MHz, 6 MHz, 8 MHz, 10 MHz, 20 MHz, 40 MHz, 80 MHz (with contiguous bandwidths) or 80+80 MHz (160 MHz) (with non-contiguous bandwidths). In some embodiments, a 920 MHz channel bandwidth may be used. The scope of the embodiments is not limited with respect to the above center frequencies however.

FIG. 8 illustrates WLAN FEM circuitry 704 a in accordance with some embodiments. Although the example of FIG. 8 is described in conjunction with the WLAN FEM circuitry 704 a, the example of FIG. 8 may be described in conjunction with the example BT FEM circuitry 704 b (FIG. 7), although other circuitry configurations may also be suitable.

In some embodiments, the FEM circuitry 704 a may include a TX/RX switch 802 to switch between transmit mode and receive mode operation. The FEM circuitry 704 a may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry 704 a may include a low-noise amplifier (LNA) 806 to amplify received RF signals 803 and provide the amplified received RF signals 807 as an output (e.g., to the radio IC circuitry 706 a-b (FIG. 7)). The transmit signal path of the circuitry 704 a may include a power amplifier (PA) to amplify input RF signals 809 (e.g., provided by the radio IC circuitry 706 a-b), and one or more filters 812, such as band-pass filters (BPFs), low-pass filters (LPFs) or other types of filters, to generate RF signals 815 for subsequent transmission (e.g., by one or more of the antennas 701 (FIG. 7)) via an example duplexer 814.

In some dual-mode embodiments for Wi-Fi communication, the FEM circuitry 704 a may be configured to operate in either the 2.4 GHz frequency spectrum or the 5 GHz frequency spectrum. In these embodiments, the receive signal path of the FEM circuitry 704 a may include a receive signal path duplexer 804 to separate the signals from each spectrum as well as provide a separate LNA 806 for each spectrum as shown. In these embodiments, the transmit signal path of the FEM circuitry 704 a may also include a power amplifier 810 and a filter 812, such as a BPF, an LPF or another type of filter for each frequency spectrum and a transmit signal path duplexer 804 to provide the signals of one of the different spectrums onto a single transmit path for subsequent transmission by the one or more of the antennas 701 (FIG. 7). In some embodiments, BT communications may utilize the 2.4 GHz signal paths and may utilize the same FEM circuitry 704 a as the one used for WLAN communications.

FIG. 9 illustrates radio IC circuitry 706 a in accordance with some embodiments. The radio IC circuitry 706 a is one example of circuitry that may be suitable for use as the WLAN or BT radio IC circuitry 706 a/706 b (FIG. 7), although other circuitry configurations may also be suitable. Alternatively, the example of FIG. 9 may be described in conjunction with the example BT radio IC circuitry 706 b.

In some embodiments, the radio IC circuitry 706 a may include a receive signal path and a transmit signal path. The receive signal path of the radio IC circuitry 706 a may include at least mixer circuitry 902, such as, for example, down-conversion mixer circuitry, amplifier circuitry 906 and filter circuitry 908. The transmit signal path of the radio IC circuitry 706 a may include at least filter circuitry 912 and mixer circuitry 914, such as, for example, up-conversion mixer circuitry. Radio IC circuitry 706 a may also include synthesizer circuitry 904 for synthesizing a frequency 905 for use by the mixer circuitry 902 and the mixer circuitry 914. The mixer circuitry 902 and/or 914 may each, according to some embodiments, be configured to provide direct conversion functionality. The latter type of circuitry presents a much simpler architecture as compared with standard super-heterodyne mixer circuitries, and any flicker noise brought about by the same may be alleviated for example through the use of OFDM modulation. FIG. 9 illustrates only a simplified version of a radio IC circuitry, and may include, although not shown, embodiments where each of the depicted circuitries may include more than one component. For instance, mixer circuitry 914 may each include one or more mixers, and filter circuitries 908 and/or 912 may each include one or more filters, such as one or more BPFs and/or LPFs according to application needs. For example, when mixer circuitries are of the direct-conversion type, they may each include two or more mixers.

In some embodiments, mixer circuitry 902 may be configured to down-convert RF signals 807 received from the FEM circuitry 704 a-b (FIG. 7) based on the synthesized frequency 905 provided by synthesizer circuitry 904. The amplifier circuitry 906 may be configured to amplify the down-converted signals and the filter circuitry 908 may include an LPF configured to remove unwanted signals from the down-converted signals to generate output baseband signals 907. Output baseband signals 907 may be provided to the baseband processing circuitry 708 a-b (FIG. 7) for further processing. In some embodiments, the output baseband signals 907 may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 902 may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 914 may be configured to up-convert input baseband signals 911 based on the synthesized frequency 905 provided by the synthesizer circuitry 904 to generate RF output signals 809 for the FEM circuitry 704 a-b. The baseband signals 911 may be provided by the baseband processing circuitry 708 a-b and may be filtered by filter circuitry 912. The filter circuitry 912 may include an LPF or a BPF, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 902 and the mixer circuitry 914 may each include two or more mixers and may be arranged for quadrature down-conversion and/or up-conversion respectively with the help of synthesizer 904. In some embodiments, the mixer circuitry 902 and the mixer circuitry 914 may each include two or more mixers each configured for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 902 and the mixer circuitry 914 may be arranged for direct down-conversion and/or direct up-conversion, respectively. In some embodiments, the mixer circuitry 902 and the mixer circuitry 914 may be configured for super-heterodyne operation, although this is not a requirement.

Mixer circuitry 902 may comprise, according to one embodiment: quadrature passive mixers (e.g., for the in-phase (I) and quadrature phase (Q) paths). In such an embodiment, RF input signal 807 from FIG. 9 may be down-converted to provide I and Q baseband output signals to be sent to the baseband processor.

Quadrature passive mixers may be driven by zero and ninety-degree time-varying LO switching signals provided by a quadrature circuitry which may be configured to receive a LO frequency (fLO) from a local oscillator or a synthesizer, such as LO frequency 905 of synthesizer 904 (FIG. 9). In some embodiments, the LO frequency may be the carrier frequency, while in other embodiments, the LO frequency may be a fraction of the carrier frequency (e.g., one-half the carrier frequency, one-third the carrier frequency). In some embodiments, the zero and ninety-degree time-varying switching signals may be generated by the synthesizer, although the scope of the embodiments is not limited in this respect.

In some embodiments, the LO signals may differ in duty cycle (the percentage of one period in which the LO signal is high) and/or offset (the difference between start points of the period). In some embodiments, the LO signals may have an 85% duty cycle and an 80% offset. In some embodiments, each branch of the mixer circuitry (e.g., the in-phase (I) and quadrature phase (Q) path) may operate at an 80% duty cycle, which may result in a significant reduction is power consumption.

The RF input signal 807 (FIG. 8) may comprise a balanced signal, although the scope of the embodiments is not limited in this respect. The I and Q baseband output signals may be provided to low-noise amplifier, such as amplifier circuitry 906 (FIG. 9) or to filter circuitry 908 (FIG. 9).

In some embodiments, the output baseband signals 907 and the input baseband signals 911 may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals 907 and the input baseband signals 911 may be digital baseband signals. In these alternate embodiments, the radio IC circuitry may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry.

In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, or for other spectrums not mentioned here, although the scope of the embodiments is not limited in this respect.

In some embodiments, the synthesizer circuitry 904 may be a fractional-N synthesizer or a fractional N/N+1 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 904 may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider. According to some embodiments, the synthesizer circuitry 904 may include digital synthesizer circuitry. An advantage of using a digital synthesizer circuitry is that, although it may still include some analog components, its footprint may be scaled down much more than the footprint of an analog synthesizer circuitry. In some embodiments, frequency input into synthesizer circuitry 904 may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. A divider control input may further be provided by either the baseband processing circuitry 708 a-b (FIG. 7) depending on the desired output frequency 905. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table (e.g., within a Wi-Fi card) based on a channel number and a channel center frequency as determined or indicated by the example application processor 710. The application processor 710 may include, or otherwise be connected to, one of the example secure signal converter 101 or the example received signal converter 103 (e.g., depending on which device the example radio architecture is implemented in).

In some embodiments, synthesizer circuitry 904 may be configured to generate a carrier frequency as the output frequency 905, while in other embodiments, the output frequency 905 may be a fraction of the carrier frequency (e.g., one-half the carrier frequency, one-third the carrier frequency). In some embodiments, the output frequency 905 may be a LO frequency (fLO).

FIG. 10 illustrates a functional block diagram of baseband processing circuitry 708 a in accordance with some embodiments. The baseband processing circuitry 708 a is one example of circuitry that may be suitable for use as the baseband processing circuitry 708 a (FIG. 7), although other circuitry configurations may also be suitable. Alternatively, the example of FIG. 9 may be used to implement the example BT baseband processing circuitry 708 b of FIG. 7.

The baseband processing circuitry 708 a may include a receive baseband processor (RX BBP) 1002 for processing receive baseband signals 909 provided by the radio IC circuitry 706 a-b (FIG. 7) and a transmit baseband processor (TX BBP) 1004 for generating transmit baseband signals 911 for the radio IC circuitry 706 a-b. The baseband processing circuitry 708 a may also include control logic 1006 for coordinating the operations of the baseband processing circuitry 708 a.

In some embodiments (e.g., when analog baseband signals are exchanged between the baseband processing circuitry 708 a-b and the radio IC circuitry 706 a-b), the baseband processing circuitry 708 a may include ADC 1010 to convert analog baseband signals 1009 received from the radio IC circuitry 706 a-b to digital baseband signals for processing by the RX BBP 1002. In these embodiments, the baseband processing circuitry 708 a may also include DAC 1012 to convert digital baseband signals from the TX BBP 1004 to analog baseband signals 1011.

In some embodiments that communicate OFDM signals or OFDMA signals, such as through baseband processor 708 a, the transmit baseband processor 1004 may be configured to generate OFDM or OFDMA signals as appropriate for transmission by performing an inverse fast Fourier transform (IFFT). The receive baseband processor 1002 may be configured to process received OFDM signals or OFDMA signals by performing an FFT. In some embodiments, the receive baseband processor 1002 may be configured to detect the presence of an OFDM signal or OFDMA signal by performing an autocorrelation, to detect a preamble, such as a short preamble, and by performing a cross-correlation, to detect a long preamble. The preambles may be part of a predetermined frame structure for Wi-Fi communication.

Referring back to FIG. 7, in some embodiments, the antennas 701 (FIG. 7) may each comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (MIMO) embodiments, the antennas may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result. Antennas 701 may each include a set of phased-array antennas, although embodiments are not so limited.

Although the radio architecture 105A, 105B is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements may refer to one or more processes operating on one or more processing elements.

The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments. The terms “computing device,” “user device,” “communication station,” “station,” “handheld device,” “mobile device,” “wireless device” and “user equipment” (UE) as used herein refers to a wireless communication device such as a cellular telephone, a smartphone, a tablet, a netbook, a wireless terminal, a laptop computer, a femtocell, a high data rate (HDR) subscriber station, an access point, a printer, a point of sale device, an access terminal, or other personal communication system (PCS) device. The device may be either mobile or stationary.

As used within this document, the term “communicate” is intended to include transmitting, or receiving, or both transmitting and receiving. This may be particularly useful in claims when describing the organization of data that is being transmitted by one device and received by another, but only the functionality of one of those devices is required to infringe the claim. Similarly, the bidirectional exchange of data between two devices (both devices transmit and receive during the exchange) may be described as “communicating,” when only the functionality of one of those devices is being claimed. The term “communicating” as used herein with respect to a wireless communication signal includes transmitting the wireless communication signal and/or receiving the wireless communication signal. For example, a wireless communication unit, which is capable of communicating a wireless communication signal, may include a wireless transmitter to transmit the wireless communication signal to at least one other wireless communication unit, and/or a wireless communication receiver to receive the wireless communication signal from at least one other wireless communication unit.

As used herein, unless otherwise specified, the use of the ordinal adjectives “first,” “second,” “third,” etc., to describe a common object, merely indicates that different instances of like objects are being referred to and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

The term “access point” (AP) as used herein may be a fixed station. An access point may also be referred to as an access node, a base station, an evolved node B (eNodeB), or some other similar terminology known in the art. An access terminal may also be called a mobile station, user equipment (UE), a wireless communication device, or some other similar terminology known in the art. Embodiments disclosed herein generally pertain to wireless networks. Some embodiments may relate to wireless networks that operate in accordance with one of the IEEE 802.11 standards.

Some embodiments may be used in conjunction with various devices and systems, for example, a personal computer (PC), a desktop computer, a mobile computer, a laptop computer, a notebook computer, a tablet computer, a server computer, a handheld computer, a handheld device, a personal digital assistant (PDA) device, a handheld PDA device, an on-board device, an off-board device, a hybrid device, a vehicular device, a non-vehicular device, a mobile or portable device, a consumer device, a non-mobile or non-portable device, a wireless communication station, a wireless communication device, a wireless access point (AP), a wired or wireless router, a wired or wireless modem, a video device, an audio device, an audio-video (A/V) device, a wired or wireless network, a wireless area network, a wireless video area network (WVAN), a local area network (LAN), a wireless LAN (WLAN), a personal area network (PAN), a wireless PAN (WPAN), and the like.

Some embodiments may be used in conjunction with one way and/or two-way radio communication systems, cellular radio-telephone communication systems, a mobile phone, a cellular telephone, a wireless telephone, a personal communication system (PCS) device, a PDA device which incorporates a wireless communication device, a mobile or portable global positioning system (GPS) device, a device which incorporates a GPS receiver or transceiver or chip, a device which incorporates an RFID element or chip, a multiple input multiple output (MIMO) transceiver or device, a single input multiple output (SIMO) transceiver or device, a multiple input single output (MIS 0) transceiver or device, a device having one or more internal antennas and/or external antennas, digital video broadcast (DVB) devices or systems, multi-standard radio devices or systems, a wired or wireless handheld device, e.g., a smartphone, a wireless application protocol (WAP) device, or the like.

Some embodiments may be used in conjunction with one or more types of wireless communication signals and/or systems following one or more wireless communication protocols, for example, radio frequency (RF), infrared (IR), frequency-division multiplexing (FDM), orthogonal FDM (OFDM), time-division multiplexing (TDM), time-division multiple access (TDMA), extended TDMA (E-TDMA), general packet radio service (GPRS), extended GPRS, code-division multiple access (CDMA), wideband CDMA (WCDMA), CDMA 2000, single-carrier CDMA, multi-carrier CDMA, multi-carrier modulation (MDM), discrete multi-tone (DMT), Bluetooth®, global positioning system (GPS), Wi-Fi, Wi-Max, ZigBee, ultra-wideband (UWB), global system for mobile communications (GSM), 2G, 2.5G, 3G, 3.5G, 4G, fifth generation (5G) mobile networks, 3GPP, long term evolution (LTE), LTE advanced, enhanced data rates for GSM Evolution (EDGE), or the like. Other embodiments may be used in various other devices, systems, and/or networks.

The following examples pertain to further embodiments.

Example 1 may include a device comprising processing circuitry coupled to storage, the processing circuitry configured to: cause to send a null data packet announcement (NDPA) frame to a responding station device (RSTA); cause to send a first sounding null data packet (NDP) frame comprising one or more fields formatted to support 2.4 gigahertz (GHz) and 5 GHz bands in a non-trigger-based ranging measurement with the RSTA; and identify after a passage of a short inter-frame space (SIFS) time a second NDP frame received from the RSTA; and identify a location measurement report frame from the RSTA.

Example 2 may include the device of example 1 and/or some other example herein, wherein the one or more fields include an high-efficiency long training field (HE-LTF) comprising one or more symbols.

Example 3 may include the device of example 2 and/or some other example herein, wherein a first symbol of the one or more symbols may be preceded by a first guard interval and wherein a second symbols of the one or more symbols may be preceded by a second guard interval.

Example 4 may include the device of example 3 and/or some other example herein, wherein the first guard interval and the second guard interval are zero power guard intervals.

Example 5 may include the device of example 1 and/or some other example herein, wherein a last field of the one or more fields may be preceded by a zero power guard interval.

Example 6 may include the device of example 1 and/or some other example herein, wherein the one or more fields include a first long training field (LTF) and a second LTF, wherein the second LTF has the same number of symbols as the first LTF.

Example 7 may include the device of example 6 and/or some other example herein, wherein the first LTF comprises one or more first symbols, wherein the second LTF comprises one or more second symbols, and wherein each one of the one or more first symbols and each one of the one or more second symbols are preceded by a zero power guard interval.

Example 8 may include the device of example 1 and/or some other example herein, further comprising a transceiver configured to transmit and receive wireless signals.

Example 9 may include the device of example 8 and/or some other example herein, further comprising an antenna coupled to the transceiver to cause to send the NDP frame.

Example 10 may include a non-transitory computer-readable medium storing computer-executable instructions which when executed by one or more processors result in performing operations comprising: causing to send a null data packet announcement (NDPA) frame to a responding station device (RSTA); causing to send a first sounding null data packet (NDP) frame comprising one or more fields formatted to support 2.4 gigahertz (GHz) and 5 GHz bands in a non-trigger-based ranging measurement with the RSTA; and identifying after a passage of a short inter-frame space (SIFS) time a second NDP frame received from the RSTA; and identifying a location measurement report frame from the RSTA.

Example 11 may include the non-transitory computer-readable medium of example 10 and/or some other example herein, wherein the one or more fields include an high-efficiency long training field (HE-LTF) comprising one or more symbols.

Example 12 may include the non-transitory computer-readable medium of example 11 and/or some other example herein, wherein a first symbol of the one or more symbols may be preceded by a first guard interval and wherein a second symbols of the one or more symbols may be preceded by a second guard interval.

Example 13 may include the non-transitory computer-readable medium of example 12 and/or some other example herein, wherein the first guard interval and the second guard interval are zero power guard intervals.

Example 14 may include the non-transitory computer-readable medium of example 10 and/or some other example herein, wherein a last field of the one or more fields may be preceded by a zero power guard interval.

Example 15 may include the non-transitory computer-readable medium of example 10 and/or some other example herein, wherein the one or more fields include a first long training field (LTF) and a second LTF, wherein the second LTF has the same number of symbols as the first LTF.

Example 16 may include the non-transitory computer-readable medium of example 15 and/or some other example herein, wherein the first LTF comprises one or more first symbols, wherein the second LTF comprises one or more second symbols, and wherein each one of the one or more first symbols and each one of the one or more second symbols are preceded by a zero power guard interval.

Example 17 may include a method comprising: causing to send a null data packet announcement (NDPA) frame to a responding station device (RSTA); causing to send a first sounding null data packet (NDP) frame comprising one or more fields formatted to support 2.4 gigahertz (GHz) and 5 GHz bands in a non-trigger-based ranging measurement with the RSTA; and identifying after a passage of a short inter-frame space (SIFS) time a second NDP frame received from the RSTA; and identifying a location measurement report frame from the RSTA.

Example 18 may include the method of example 17 and/or some other example herein, wherein the one or more fields include an high-efficiency long training field (HE-LTF) comprising one or more symbols.

Example 19 may include the method of example 18 and/or some other example herein, wherein a first symbol of the one or more symbols may be preceded by a first guard interval and wherein a second symbols of the one or more symbols may be preceded by a second guard interval.

Example 20 may include the method of example 19 and/or some other example herein, wherein the first guard interval and the second guard interval are zero power guard intervals.

Example 21 may include the method of example 17 and/or some other example herein, wherein a last field of the one or more fields may be preceded by a zero power guard interval.

Example 22 may include the method of example 17 and/or some other example herein, wherein the one or more fields include a first long training field (LTF) and a second LTF, wherein the second LTF has the same number of symbols as the first LTF.

Example 23 may include the method of example 22 and/or some other example herein, wherein the first LTF comprises one or more first symbols, wherein the second LTF comprises one or more second symbols, and wherein each one of the one or more first symbols and each one of the one or more second symbols are preceded by a zero power guard interval.

Example 24 may include an apparatus comprising means for: causing to send a null data packet announcement (NDPA) frame to a responding station device (RSTA); causing to send a first sounding null data packet (NDP) frame comprising one or more fields formatted to support 2.4 gigahertz (GHz) and 5 GHz bands in a non-trigger-based ranging measurement with the RSTA; and identifying after a passage of a short inter-frame space (SIFS) time a second NDP frame received from the RSTA; and identifying a location measurement report frame from the RSTA.

Example 25 may include the apparatus of example 24 and/or some other example herein, wherein the one or more fields include an high-efficiency long training field (HE-LTF) comprising one or more symbols.

Example 26 may include the apparatus of example 25 and/or some other example herein, wherein a first symbol of the one or more symbols may be preceded by a first guard interval and wherein a second symbols of the one or more symbols may be preceded by a second guard interval.

Example 27 may include the apparatus of example 26 and/or some other example herein, wherein the first guard interval and the second guard interval are zero power guard intervals.

Example 28 may include the apparatus of example 24 and/or some other example herein, wherein a last field of the one or more fields may be preceded by a zero power guard interval.

Example 29 may include the apparatus of example 24 and/or some other example herein, wherein the one or more fields include a first long training field (LTF) and a second LTF, wherein the second LTF has the same number of symbols as the first LTF.

Example 30 may include the apparatus of example 29 and/or some other example herein, wherein the first LTF comprises one or more first symbols, wherein the second LTF comprises one or more second symbols, and wherein each one of the one or more first symbols and each one of the one or more second symbols are preceded by a zero power guard interval.

Example 31 may include one or more non-transitory computer-readable media comprising instructions to cause an electronic device, upon execution of the instructions by one or more processors of the electronic device, to perform one or more elements of a method described in or related to any of examples 1-30, or any other method or process described herein.

Example 32 may include an apparatus comprising logic, modules, and/or circuitry to perform one or more elements of a method described in or related to any of examples 1-30, or any other method or process described herein.

Example 33 may include a method, technique, or process as described in or related to any of examples 1-30, or portions or parts thereof.

Example 34 may include an apparatus comprising: one or more processors and one or more computer readable media comprising instructions that, when executed by the one or more processors, cause the one or more processors to perform the method, techniques, or process as described in or related to any of examples 1-30, or portions thereof.

Example 35 may include a method of communicating in a wireless network as shown and described herein.

Example 36 may include a system for providing wireless communication as shown and described herein.

Example 37 may include a device for providing wireless communication as shown and described herein.

Embodiments according to the invention are in particular disclosed in the attached claims directed to a method, a storage medium, a device and a computer program product, wherein any feature mentioned in one claim category, e.g., method, can be claimed in another claim category, e.g., system, as well. The dependencies or references back in the attached claims are chosen for formal reasons only. However, any subject matter resulting from a deliberate reference back to any previous claims (in particular multiple dependencies) can be claimed as well, so that any combination of claims and the features thereof are disclosed and can be claimed regardless of the dependencies chosen in the attached claims. The subject-matter which can be claimed comprises not only the combinations of features as set out in the attached claims but also any other combination of features in the claims, wherein each feature mentioned in the claims can be combined with any other feature or combination of other features in the claims. Furthermore, any of the embodiments and features described or depicted herein can be claimed in a separate claim and/or in any combination with any embodiment or feature described or depicted herein or with any of the features of the attached claims.

The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments.

Embodiments according to the disclosure are in particular disclosed in the attached claims directed to a method, a storage medium, a device and a computer program product, wherein any feature mentioned in one claim category, e.g., method, can be claimed in another claim category, e.g., system, as well. The dependencies or references back in the attached claims are chosen for formal reasons only. However, any subject matter resulting from a deliberate reference back to any previous claims (in particular multiple dependencies) can be claimed as well, so that any combination of claims and the features thereof are disclosed and can be claimed regardless of the dependencies chosen in the attached claims. The subject-matter which can be claimed comprises not only the combinations of features as set out in the attached claims but also any other combination of features in the claims, wherein each feature mentioned in the claims can be combined with any other feature or combination of other features in the claims. Furthermore, any of the embodiments and features described or depicted herein can be claimed in a separate claim and/or in any combination with any embodiment or feature described or depicted herein or with any of the features of the attached claims.

The foregoing description of one or more implementations provides illustration and description, but is not intended to be exhaustive or to limit the scope of embodiments to the precise form disclosed. Modifications and variations are possible in light of the above teachings or may be acquired from practice of various embodiments.

Certain aspects of the disclosure are described above with reference to block and flow diagrams of systems, methods, apparatuses, and/or computer program products according to various implementations. It will be understood that one or more blocks of the block diagrams and flow diagrams, and combinations of blocks in the block diagrams and the flow diagrams, respectively, may be implemented by computer-executable program instructions. Likewise, some blocks of the block diagrams and flow diagrams may not necessarily need to be performed in the order presented, or may not necessarily need to be performed at all, according to some implementations.

These computer-executable program instructions may be loaded onto a special-purpose computer or other particular machine, a processor, or other programmable data processing apparatus to produce a particular machine, such that the instructions that execute on the computer, processor, or other programmable data processing apparatus create means for implementing one or more functions specified in the flow diagram block or blocks. These computer program instructions may also be stored in a computer-readable storage media or memory that may direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable storage media produce an article of manufacture including instruction means that implement one or more functions specified in the flow diagram block or blocks. As an example, certain implementations may provide for a computer program product, comprising a computer-readable storage medium having a computer-readable program code or program instructions implemented therein, said computer-readable program code adapted to be executed to implement one or more functions specified in the flow diagram block or blocks. The computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational elements or steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions that execute on the computer or other programmable apparatus provide elements or steps for implementing the functions specified in the flow diagram block or blocks.

Accordingly, blocks of the block diagrams and flow diagrams support combinations of means for performing the specified functions, combinations of elements or steps for performing the specified functions and program instruction means for performing the specified functions. It will also be understood that each block of the block diagrams and flow diagrams, and combinations of blocks in the block diagrams and flow diagrams, may be implemented by special-purpose, hardware-based computer systems that perform the specified functions, elements or steps, or combinations of special-purpose hardware and computer instructions.

Conditional language, such as, among others, “can,” “could,” “might,” or “may,” unless specifically stated otherwise, or otherwise understood within the context as used, is generally intended to convey that certain implementations could include, while other implementations do not include, certain features, elements, and/or operations. Thus, such conditional language is not generally intended to imply that features, elements, and/or operations are in any way required for one or more implementations or that one or more implementations necessarily include logic for deciding, with or without user input or prompting, whether these features, elements, and/or operations are included or are to be performed in any particular implementation.

Many modifications and other implementations of the disclosure set forth herein will be apparent having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the disclosure is not to be limited to the specific implementations disclosed and that modifications and other implementations are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. 

What is claimed is:
 1. A device for using null data packets (NDPs), the device comprising processing circuitry coupled to storage, the processing circuitry configured to: generate a symbol for a high-efficiency long training field (HE-LTF) of an NDP; generate the HE-LTF comprising a first zero-power guard interval and the symbol, the first zero-power guard interval preceding the symbol; generate the NDP, the NDP comprising the HE-LTF, the symbol preceding a second zero-power guard interval in the NDP, the second zero-power guard interval preceding a packet extension field in the NDP; and transmit the NDP to a second device.
 2. The device of claim 1, wherein the first zero-power guard interval and the symbol are associated with a secure mode.
 3. The device of claim 1, wherein the HE-LTF has a duration of 8 microseconds.
 4. The device of claim 1, wherein the HE-LTF has a duration of 7.2 microseconds.
 5. The device of claim 1, wherein the processing circuitry is further configured to: generate a second symbol for a second HE-LTF of the NDP, wherein the symbol precedes a third guard interval in the NDP, wherein the third guard interval precedes the second symbol in the NDP, and wherein the second symbol precedes the second zero-power guard interval in the NDP.
 6. The device of claim 1, wherein the second zero-power guard interval and the packet extension field have a total duration of 4 microseconds.
 7. The device of claim 1, wherein the processing circuitry is further configured to determine, based on a number of space-time streams associated with the transmission, a number of HE-LTFs to include in the NDP.
 8. The device of claim 1, further comprising a transceiver configured to transmit and receive wireless signals, wherein the wireless signals comprise the NDP.
 9. The device of claim 8, further comprising an antenna coupled to the transceiver.
 10. A non-transitory computer-readable medium storing computer-executable instructions which when executed by one or more processors of a first device result in performing operations comprising: generating, by a first device, a symbol for a high-efficiency long training field (HE-LTF) of a null data packet (NDP); generating the HE-LTF comprising a first zero-power guard interval and the symbol, the first zero-power guard interval preceding the symbol; generating the NDP, the NDP comprising the HE-LTF, the symbol preceding a second zero-power guard interval in the NDP, the second zero-power guard interval preceding a packet extension field in the NDP; and transmitting the NDP to a second device.
 11. The non-transitory computer-readable medium of claim 10, wherein the first zero-power guard interval and the symbol are associated with a secure mode.
 12. The non-transitory computer-readable medium of claim 10, wherein the HE-LTF has a duration of 8 microseconds.
 13. The non-transitory computer-readable medium of claim 10, wherein the HE-LTF has a duration of 7.2 microseconds.
 14. The non-transitory computer-readable medium of claim 10, the operations further comprising: generating a second symbol for a second HE-LTF of the NDP, wherein the symbol precedes a third guard interval in the NDP, wherein the third guard interval precedes the second symbol in the NDP, and wherein the second symbol precedes the second zero-power guard interval in the NDP.
 15. The non-transitory computer-readable medium of claim 10, wherein the second zero-power guard interval and the packet extension field have a total duration of 4 microseconds.
 16. A method for using null data packets (NDPs), the method comprising: generating, by processing circuitry of a first device, a symbol for a high-efficiency long training field (HE-LTF) of a null data packet (NDP); generating, by the processing circuitry, the HE-LTF comprising a first zero-power guard interval and the symbol, the first zero-power guard interval preceding the symbol; generating, by the processing circuitry, the NDP, the NDP comprising the HE-LTF, the symbol preceding a second zero-power guard interval in the NDP, the second zero-power guard interval preceding a packet extension field in the NDP; and transmitting, by the processing circuitry, the NDP to a second device.
 17. The method of claim 16, wherein the first zero-power guard interval and the symbol are associated with a secure mode.
 18. The method of claim 16, wherein the HE-LTF has a duration of 8 microseconds.
 19. The method of claim 16, wherein the HE-LTF has a duration of 7.2 microseconds.
 20. The method of claim 16, further comprising: generating a second symbol for a second HE-LTF of the NDP, wherein the symbol precedes a third guard interval in the NDP, wherein the third guard interval precedes the second symbol in the NDP, and wherein the second symbol precedes the second zero-power guard interval in the NDP. 